Tapping attachment

ABSTRACT

A tapping or threading attachment device for lathes and other machines. Said device having spring means for initially urging a tap or other threading tool into engagement with a work piece for starting a tapping or threading operation. Said spring means also acting to condition the device by reverse rotation of the work piece to cause withdrawal of the threading tool from the work piece upon completion of the threading operation.

United States Patent [191 Khachigian TAPPING ATTACHMENT [76] Inventor: John Khachigian, 42 Capitol Ave.,

Hartford, Conn. 061 13 [22] Filed: July 11, 1972 [21] Appl. N0.: 270,655

[52] US. Cl. 10/134, 10/136 R [51] Int. Cl. B23g l/00 [58] Field of Search lO/89 H, 89 F, 129 R, 134,

10/135 R, 139 R, 136 R; 408/142, 141

[56] References Cited UNITED STATES PATENTS 808,981 1/1906 Goodrich 408/141 809,257 l/l906 Hanson 408/141 2,340,477 2/1944 Kurse 10/129 R 2,505,335 4/1950 Miller 10/89 H 2,635,260 4/1953 Chapin 10/135 R 2,881,454 4/1959 Moneymaker 10/89 H 3,011,185 12/1961 Khachigian 10/129 R 3,179,965 4/1965 Khachigian 408/142 [451 July 2, 1974 3,371,364 3/1968 Johnson 10/89 H 3,466,681 9/1969 Benjamin et a1 10/129 R' FOREIGN PATENTS OR APPLICATIONS 153,133 1/1956 Sweden 10/135 407,391 12/1924 Germany 10/96 R Primary Examiner-Char1es W. Lanham Assistant Examiner-E. M. Combs [57] ABSTRACT 3 Claims, 7 Drawing Figures TAPPING ATTACHMENT SUMMARY OF THE INVENTION The present invention provides certain improvements over the devices described in my US. Pats. No. 3,01 1,185, issued Dec. 5, 1961 and US. Pat. No. 3,179,965, issued Apr. 27, 1965; the said improvements providing for initially urging the threading tool into engagement with the work piece and also for automatically conditioning the device to cause withdrawal of the tool from the work piece upon completion of a threading operation.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 of the accompanying drawings is a sectional side view of the device embodying the present invention.

FIG. 2 is a sectional end view on line 2-2 of FIG. 1.

FIG. 3 is a partly sectional side view showing said device in the position for starting the threading operation.

FIG. 4 is a sectional side view illustrating the operation of the device during the threading of a work piece.

FIG. 5 is a sectional end view on line 5-5 of FIG. 4.

FIGS. 6 and 7 are diagrammatic views further illustrating the operation of said device.

DESCRIPTION OF THE INVENTION The primary object of this invention is to provide certain improvements, .over the devices of said patents, which will further facilitate the use and operation of my improved tapping attachment described herein.

As illustrated in the drawings the numeral 5 indicates a spindle having a taperedshank 6 with a body portion 7 extending therefrom. The said portion is formed to provide elongated, longitudinal grooves 8-8 in diametrically opposite sides thereof and terminating in an annular groove 9 adjacent to a head portion 10 at the forward end of the body portion 7. The forward portions of the grooves 8-8 (the lower side portion of the front groove and the upper side of the rear portion groove in FIG. 1) are helical, as shown at 11-11, and leadtoward the annular groove 9.

A carrier member, in-the form of a sleeve 12, is slidably and rotatably mounted on the body portion of the spindle and has a slot 13, in the forward end thereof, in which are mounted pairs of radially slidable opposed chuck jaws 14-14 and 15-15, each pair having oppositely tapered outer surfaces 16-16 engageable with oppositely tapered annular inner surfaces on a chuck sleeve 17, that is keyed to the sleeve 12 by a key 18, and a chuck sleeve 19 which is threaded to the sleeve 17 and rotatable to actuate the pairs of chuck jaws 14-14 and 15-15 to secure the tap 20 to said device.

The said carrier member has an enlarged portion 21 with radial slots 22-22 in which are slidably mounted slide blocks 23-23 having pins 24-24 extending therethrough into the grooves 8-8 and compression springs 25-25 are contained in said slots to urge the blocks rearwardly.

The said blocks areretained in operative position by a sleeve 26 which surrounds the portion 21 and is secured thereto by a screw 27.

Push pins 28-28 are longitudinally slidable in the portion 21 and project rearwardly therefrom; said push pins engage with the slide blocks 23-23 and are operated by a collar 29 which is slidable on the spindle 5 and adjustably secured thereto by a screw 30; gradua tions 31 being provided on the spindle for locating said collar.

In the use of said device, it is mounted in the tailstock of a lathe, or like machine, by the shank 6, and the work piece, indicated at 32, in which a hole is to be tapped, is held in a stationary position while being rotated.

The threading device is then moved towards the work piece until the end of the tap 20 engagesthe hole in the work piece and the collar 29 engages the pins 28-28 and forces the blocks 23-23 forwardly and compresses the springs 25-25, as shown in FIG. 3; thus urging the tap into threading engagement with the hole in the work piece and starting the threading operation.

As the threading continues, the carrier sleeve 12 and its entire assembly is pulled forwardly by the tap and is aided in its forward movement by the action of the helical side portions 1 1-11 of the grooves on the 'pins 24-24 until said pins slide over the corners 32-32 at the forward ends of the said helical portions 11-11, as

shown in FIGS. 4 and 6, and thereby accelerate the forward movement of the pins 24-24 to pull the slide blocks 23-23 forwardly and compress the springs 25-25. The said pins then enter the annular groove 9 and the entire carrier sleeve assembly rotates with the work piece and the entry of the tap into the hole in the work piece is terminated.

The rotation of the work piece is then reversed and the assembly is thereby rotated in the reverse direction upon the spindle 5. The tension in the springs 25-25 will then cause the pins 24-24 to partly enter the grooves 8-8 and engage the sharp corners 33-33 of the opposite sides thereof, as shown in FIG. 7, whereby reverse rotation of the tap with the work piece is terminated and the assembly will move rearwardly on the spindle 5 until the tap is withdrawn from the work piece and the threading operation is completed.

It will be noted that, by adjusting the collar 29 on the spindle, along the graduations 31, the starting position for the operation of the pins 24-24 may be controlled so that the distance traveled by the tap before said pins reach the annular groove 9 may be varied to obtain any desired length of thread in a work piece.

I claim:

1. A threading device including a spindle with a body portion having in its peripheral surface a longitudinal groove and an annular groove at the forward end of said longitudinal groove communicating therewith, a carrier member axially slidable and rotatable on said body portion over said grooves, a pin projecting from said carrier member and movable in said grooves, said longitudinal groove having a helical side portion leading to said annular groove and engageable by said pin to urge forward axial movement of said carrier member in response to a rotational force applied thereto in a direction to force said pin against said helical side portion, said pin being adapted to pass from said helical side portion into said annular groove to release said carrier member for free rotation relatively to said spindle in the direction of said force, said helical side portion having a rounded corner at said annular groove to accelerate forward movement of said pin from the helical portion into the annular groove, and a spring tensioned by said accelerated movement of the pin to urge said pin rearwardly in the carrier member during free rotation of the carrier member under said force and cause said pin to engage the opposite side of the longitudinal groove upon reversed rotation of said carrier member and thereby stop reverse rotation of the carrier and cause retraction of the pin rearwardly into the longitudinal groove.

2. A threading device as set forth in claim 1 wherein said pin is mounted in a slide block slidable in a groove in the carrier member and spring is located between the starting a threading operation thereon. 

1. A threading device including a spindle with a body portion having in its peripheral surface a longitudinal groove and an annular groove at the forward end of said longitudinal groove communicating therewith, a carrier member axially slidable and rotatable on said body portion over said grooves, a pin projecting from said carrier member and movable in said grooves, said longitudinal groove having a helical side portion leading to said annular groove and engageable by said pin to urge forward axial movement of said carrier member in response to a rotational force applied thereto in a direction to force said pin against said helical side portion, said pin being adapted to pass from said helical side portion into said annular groove to release said carrier member for free rotation relatively to said spindle in the direction of said force, said helical side portion having a rounded corner at said annular groove to accelerate forward movement of said pin from the helical portion into the annular groove, and a spring tensioned by said accelerated movement of the pin to urge said pin rearwardly in the carrier member during free rotation of the carrier member under said force and cause said pin to engage the opposite side of the longitudinal groove upon reversed rotation of said carrier member and thereby stop reverse rotation of The carrier and cause retraction of the pin rearwardly into the longitudinal groove.
 2. A threading device as set forth in claim 1 wherein said pin is mounted in a slide block slidable in a groove in the carrier member and spring is located between the carrier and the block to yieldingly urge the block and pin rearwardly on said carrier.
 3. A threading device as set forth in claim 2 including a push pin slidable in the carrier member and projecting rearwardly therefrom, and a collar longitudinally adjustable on the spindle for engaging said push pin to move said block forwardly in the carrier member to compress said spring and urge the carrier member forwardly on the spindle to urge a threading tool on the carrier member into engagement with a work piece for starting a threading operation thereon. 